INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Quantum dynamical simulation of plasmon excitations in metal nanoparticles
Autor/es:
CRISTIÁN G. SÁNCHEZ; M. BELÉN OVIEDO; CHRISTIAN F. A. NEGRE
Reunión:
Congreso; XIX International Materials Research Congress 2010; 2010
Resumen:
p { margin-bottom: 0.21cm; }
Metallic
and semiconductor
nanoparticles form part of some of the most tangible present day
applications of nanostructured materials. In most cases these
applications are the result of their special optical properties.
Nanoparticles have absorptivities several orders of magnitude larger
than organic dyes and their absorption spectra can be tuned via
careful control of their size and shape [1]. The physics behind
metallic nanoparticle optical properties is the coherent oscillation
of their conduction electrons under the influence of an oscillating
electromagnetic field, the Plasmon oscillation.
In
this talk I will present some results obtained from time dependent
simulations of the quantum evolution of conduction electrons under
the influence of applied time varying electric fields.
These simulations provide a detailed picture of the excitation and
relaxation processes of Plasmon oscillations in metallic
nanoparticles including the influence of their atomistic structure
and environment. The simulations are done via real time integration
of the Liouville-von Neumann equation of motion for the reduced
single electron density matrix within self consistent tight-binding
models of varying complexity [2,3,4]. The use of tight binding models
allows for the study of particles of realistic size while at the same
time providing a quantum description of the time evolving electronic
structure.
The
following are some of the main results that we have obtained so far
and which I will present in detail in the talk:
Particle
size
and shape dependence of the absorption energy and plasmon lifetime.
Influence
of
adsorbates and alloying on the resonance energy and lifetime.
Detailed
information on the field
enhancement in the immediate neighbourhood of the particle.
[1]
U.
Kreibig and M. Volmer, Optical Properties of Metal Clusters,
Springer, New York, 1995.
[2]
M.
Elstner, D. Porezag, G. Jungnickel, J. Elsner, M. Haugk, Th. S. Suhai
and G. Seifert, Phys. Rev. B: Condens. Matter Mater. Phys., 1998, 58,
72607268.
[3]
C. F. A. Negre and C. G. Sanchez,
J. Chem. Phys., 2008, 129, 034710.
[4]
M. Belen Oviedo, Christian F. A. Negre, Cristian G. Sa´nchez, Phys.
Chem. Chem. Phys., (2010), DOI: 10.1039/b926051j.